My favorite so far is 1.5 scoops with 12-16 oz whole milk. Just can't beat that creamy awesome flavor.
That's my favorite plain with no additives.
My favorite of all time is what I just did today though....
1.5 scoops Isotean, 2tbsp honey, a few shakes of cinnamon, and skim milk (only used skim because that's what the gf brought home!).
Try it out sometime.